About The Cover

Online Cover This week's issue features a Research Article that quantitatively explores the mechanisms underlying the remarkable sensitivity of sea urchin sperm to a chemoattractant peptide released from an egg. The image depicts the sea urchin Arbacia punctulata releasing sperm, as well as an artist's rendition of the structure of the the A. punctulata K+-selective cyclic nucleotide–gated channel of sperm, which is activated by a single molecule of cGMP, enabling it to follow small changes in cGMP concentration and translate them into small changes in membrane potential. [Image: René Pascal, Center of Advanced European Studies and Research, Bonn, Germany and Hans-Dieter Grammig, Institut für Strukturbiologie und Biophysik, Jülich, Germany]